The static load plate test is the standard subgrade acceptance test for new or modernised railway lines. Examinations are performed at regular spacings on the track section and a lack of acceptance for even a single test disqualifies a section, forcing remedial treatments on the whole section. In this paper, a nondeterministic description of stiffness related to the spatial characteristics of acceptance measurement results is proposed for a more rational assessment of substructure quality. The concept is based on geostatistical analysis and one-dimensional distributions of stiffness values. The paper also proposes a new concept of rail infrastructure acceptance based on a reliability index already codified in European standards. The functioning of the postulated criterion is presented on the example of an existing railway line and the actual test results.
Keywords: deformation modulus; reliability; static load test; subgrade.